BEIRUT - Five staff members of the medical charity Medecins Sans Frontieres (MSF) were taken from their house in northern Syria on Thursday evening and have been out of contact since then, the aid group said in a statement on Friday.

MSF did not specify the nationality of the staff, their roles, or which group took them, but said it was "in contact with all the relevant stakeholders" and trying to re-establish contact with the staff.

The group, know for sending doctors to hard-to-reach conflict zones, said the staff were allegedly taken for questioning.

The government of President Bashar Assad still controls some pockets of land in northern Syria but rebels fighting for his overthrow, including hardline Islamist factions, have taken swathes of territory